@dc42 I made some video of 4th axis flying extruder.
Because I am not used to video editing, I uploaded 4 separate videos on youtube. sorry about that. Pls, visit followings.
If you need other scenes, just ask.
@dc42, Of course, you can post it on other sites.
The PTFE tube length is 280mm from extruder fitting to effector fitting.
This is significant improvement comparing to my mini KOSSEL's 450mm.
I corrected the link of the carriage view, the 4th video.
I attached a metric ruler on the 4th rail. So you can see how far and fast the extrude carriage moves up and down when effector is traveling the same z_height XY plane.
My current setup is as follows
U_axis rod Length is 300, U_tower position M669 X0 Y-100.
The carriage moves dully relative to XY position if the U_axis rod length
is set high(ex. X665 L358:358:358:600), whereas the movement is very rapid and far when U_axis rod length is set low (ex. X665 L358:358:358:300).
If I set the rod length too short (for example 200mm), the effector cannot reach U_axis' opposite(diagonal) edge. And the carriage moves too fast enough to skip steps. Firmware restricts the movement.
The ideal U_tower position seems to be the center[M669 X0 Y0] given that fitting do not wear out and the PTFE tube don't flex too much. I will try this when I am ready for gimbals similar to ZATSIT's FlyStruder.
@dc42 I made some video of 4th axis flying extruder.
Because I am not used to video editing, I uploaded 4 separate videos on youtube. sorry about that. Pls, visit followings.
If you need other scenes, just ask.
@dc42
I will in the future.
Currently, I am not prepared for the heat bed. So actual printing is not ready to show. And the 4th tower is a bit ugly.
I can take a video of bed leveling(G32,G29) though.
Is there some dryrun G_code in Reprap firmware? I can't find it.
@dc42 Other towers do act as you mentioned.
But U_axis doesn't seem to revert to the standard position.
It acts like -15mm offset. If I adopt a magnetic end_stop to avoid a collision, I could even set a positive offset I suppose.
@dc42 I Not really want the offset function anymore.
I added the following G-code to homedelta.g as your advice.
G1 Z-5 F6000 ; 5mm downward motion.
G1 U-15 F1800 S2 ; fine tune U_axis' carriage position. move down 15mm
Now I can finetune U_axis' carriage position.
Thank you very much.
@dc42
I understood.
I just want to know if you have some plan to add offset function to the new axis.
@dc42
M666 function on the new Axis,
I am actively testing the new feature changing M669 and M665 R with my delta, 300mm diameter, 410mm z_height from center to center
Here is my case.
I placed 4th_axis near the print edge. M669 X0 Y-140.
And set the rod length of this new axis as same as other towers.
When I home all the tower and bring the carriages down a little, let's say 20mm. And move the effector toward the new axis, G1 X0 Y-140.
Then 4th_tower's carriage hit its end_stop( Printer doesn't actually hit the end_stop physically, rather change z_height to avoid physical touch.)
Can it be solved by adding U_axis end_stop offset something similar to M666 and ignore end_stop sensing after homing?
When I move the carriages down 30mm from home position, so this is not a big issue. What makes me chore is every time I adjust the PTFE tube from effector to the extruder motor hanging. I have to move the end_stop to proper position physically with a wrench.
I think this can be solved by adding the end_stop offset to the new axis, such as M666.